


Not So Brotherly

by KudaKano



Category: Big Hero 6 (2014)
Genre: M/M, Sibling Incest
Language: English
Status: Completed
Published: 2014-10-27
Updated: 2014-10-27
Packaged: 2018-02-22 20:41:02
Rating: Explicit
Warnings: Underage
Chapters: 1
Words: 3,505
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/2521091
Author URL: https://archiveofourown.org/users/KudaKano/pseuds/KudaKano
Summary: <blockquote class="userstuff">
              <p>Hiro's hormones are acting up and when Tadashi gets home from school, he can barely hold back. Tadashi x Hiro smut. Warning: Underage, Incest, All that fun stuff.</p>
            </blockquote>





	Not So Brotherly

**Author's Note:**

> Warnings!: Incest, Underage, Brothers doing dirty things and liking it.
> 
> Rated: M
> 
> This is a Hidashi fic written for smallhirodork on tumblr. It was supposed to be a short fic but it ended up being WAY longer so…
> 
> Enjoy the Tadashi X Hiro smut.
> 
> (Forgive me for grammar errors.)
> 
> I'll get back to the normal brother fics after this hee hee :)

For some reason, Hiro’s hormones were going crazy today.

 

He had woken up half aroused by some dream-like fantasy and it only got worse as he continued to lay in bed. Every time he shifted, his hips rubbed against the sheets and the covers brushed against every hot spot on his body.

 

Soon he was _very_ hard and peeked over his covers to see if Tadashi was awake. He groaned when he realized his brother had already left for school.

 

It’s fine. He didn’t need Tadashi.

 

He slipped his hand underneath the covers and lightly stroked himself.  He tried thinking of something erotic to get himself off to but it quickly turned into an image of his older brother.

 

He bit his lip and sighed into the covers. He imagined Tadashi hovering over him, kissing him wetly, and pushing him into the mattress. His pace quickened and it wasn’t long before he came with a gasp, hips thrusting slightly in the afterglow.

 

There.  He was done.  Taken care of.

 

But when he got up to take a shower his mind was still in the gutter.  While washing shampoo out of his hair, his head was suddenly filled with images of Tadashi bathing. That quickly turned into an image of his older brother sliding their wet bodies together and…Hiro was touching himself again.

 

He groaned and rested his forehead against the shower door.  He stroked himself furiously until he reached his second blissful orgasm and the evidence was washing down the drain.

 

Okay, _now_ he was done.

 

Hiro dried off, pulled on some fresh clothes and began working on a new design for his battle bot.  His mind was completely focused as he opened up a new program and retrieved a pen and notebook.  However, his _body_ was clearly _not_ focused because after a few minutes he began feeling a familiar tightness in his shorts.

 

He paused and set his pen down before staring into his lap.

 

_Are you kidding me?_

He frowned and shifted in his chair, deciding to ignore it. 

 

He could not spend the whole day masturbating! He wanted to do something productive!

 

He bit his lip and continued designing. He worked for several hours without leaving his desk.  His hormones were still acting up and erotic images of Tadashi were bouncing around in the back of his head but he managed to stay focused…for a little while.

 

Soon he was on his feet and looking for another distraction.  He made his bed, straightened up his room, and even took some of his dirt laundry and threw it into the washer.  But the movement did nothing to settle his needs.  He soon found himself facedown in his Tadashi’s bed.  He could smell the lingering scent of his brother through the pillow and his hips wiggled back and forth anxiously.

 

He _needed_ Tadashi.

 

But he would have to wait for his older brother to return from school.

 

He ended up helping Aunt Cass for the rest of the day. It was a perfect distraction. He helped her take orders and clean up in the Café and when she didn’t need his help he found something random to wipe or organize.

 

Aunt Cass eventually complained about him being _too_ helpful.

 

“You’ve already cleaned every inch of the house! Go out and do something fun.” She stated as she walked by him with a coffee mug and ruffled his hair.

 

She had no idea what kind of _fun_ things were on Hiro’s mind at the moment.

 

He scooped out Mochi’s litter box and his eyes drifted to the cat-shaped clock on the wall.  It was five-thirty and Tadashi still wasn’t home.

 

Of course his brother would choose _today_ to work late on his college project.

 

By six, Hiro decided a walk around the block would help pass the time but right as he headed out the door his face collided with Tadashi’s chest.

 

“Oh! Sorry, Hiro.” His brother said as he placed a firm hand on the boy’s shoulder and took a step back.

 

Hiro had been waiting for Tadashi all day, but he wasn’t expecting his brother’s presence right at that _specific_ moment and he froze.  He got a good whiff of Tadashi‘s scent before he pulled away and the hand on his shoulder caused tingles to race up and down his skin. His cheeks burned red and he stared up at his brother in surprise.

 

Tadashi’s eyes narrowed and he looked down at Hiro with concern.

 

“You okay?” He asked softly.  He had an armload of books and two school bags on his shoulder but he shifted them and brought a hand to Hiro’s face.

 

Hiro didn’t reply, but he leaned into the hand against his cheek and stared up at Tadashi with half-lidded eyes.

 

Tadashi seemed taken aback by the heated look on his little brother’s face.  His eyes scanned the room to see if Aunt Cass was looking before he drew closer to Hiro and kissed him just below the ear.

 

“After dinner.” He whispered before pulling away and walking into the room.

 

Hiro shuddered and his fingers clung to his brother’s shirt as the older boy walked by.

 

“Hey Aunt Cass, am I too late for dinner?” Tadashi greeted their aunt and she spun around with a smile.

 

“You’re just in time!  I’m making us some _hot wings_!” She stated enthusiastically.

 

And so, they ate hot wings.

 

Hiro’s foot was tapping impatiently as he sat at the dinner table.  Tadashi and Aunt Cass were talking about college stuff but Hiro remained silent. He stared at his brother, watching him eat.  His eyes traveled up the older one’s neck and settled on his face as he bit into another chicken wing. Tadashi was a very neat eater, but even _he_ was having a hard time staying clean because of how much sauce Aunt Cass had soaked the wings in.

 

Tadashi dabbed at his cheek with a napkin before bringing a hand to his mouth and sucking a bit of sauce from his fingertip. Hiro’s eyes glued to his brother’s finger.  He licked his own lips at the sight. 

 

“Hiro, you’re _filthy_.” Aunt Cass stated.

 

Hiro immediately spit up some of the soda he was drinking and began coughing into his palm. He stared at his aunt with wide eyes.

 

“W-what?” He choked out.

 

Aunt Cass gave him a perplexed look as she bit into another chicken wing.

“You’ve got sauce all over you.” She gestured to his body with a hand full of napkins.

 

Hiro looked down to see his hands and shirt covered in orange sauce.  He couldn’t see himself but he was certain his face was covered as well.

 

“O-oh…my bad.” He mumbled and grabbed some napkins. His heart was still hammering and he sighed, feeling both relieved and _stupid_.

 

Tadashi was using the back of his hand to try and suppress his laughter.  Hiro wasn’t sure if it was because he looked silly covered in sauce or if it was because Tadashi knew what was _really_ on his brother’s mind. Perhaps _both_.

 

Afterwards, Hiro ran into the bathroom to get cleaned up while Tadashi helped their aunt with the dishes.

 

He scrubbed his hands and face in the sink and then pulled his dirty shirt off.  He took a moment to stare at his flustered face in the mirror and he pressed his cold palms against his burning cheeks.

 

“What is _wrong_ with me today?” He whispered before taking a seat on the toilet lid and resting his head against the wall. 

 

He moaned softly and his hips wiggled back and fourth against the toilet.  He wanted Tadashi _so_ badly, but he couldn’t let Aunt Cass see him like this.

 

He remained there until he could no longer hear movement in the kitchen.

 

He then cracked the bathroom door open and peeked his head out.  When he saw that all the lights were off, he quickly walked shirt-less up the stairs and into his bedroom.

 

He stopped in his tracks when he saw his brother. Tadashi’s lean form was spread out across his bed.  He was propped up slightly against the headboard and his eyes were focused on the book he was reading.

 

Hiro swallowed, suddenly feeling a bit nervous.

 

“Tadashi?” Hiro addressed him softly.

 

His brother looked up from what he was reading. His expression was warm and there was a crooked smile on his face.  He observed Hiro’s timid, shirtless form and he waited.

 

Hiro bit his lip.  He knew Tadashi would never do anything unless Hiro asked for it, but he was always a bit nervous to initiate it. 

 

“Uh…do you wanna fool around?” He asked. He shifted his weight back and forth between his feet and he smiled bashfully.

 

Tadashi’s smile grew and he chuckled a bit before closing his book and setting it on his bedside table. He brought his arms up and stretched out his whole body.  He hummed as if he was still contemplating an answer.

 

“Sure, if you want to.”  Tadashi replied.

 

Hiro was in his lap a second later and the older brother laughed a bit in surprise.

 

“Whoa! What’s gotten into you today?” He chuckled quietly.

 

Hiro could think of a million sexy comebacks but he knew Tadashi wasn’t big on dirty talk so he bit his tongue. The last thing he wanted was to ruin his brother’s mood.

 

“I-I don’t know…I just…” He trailed off and struggled to get his shorts off as he straddled Tadashi’s lap.

 

His brother placed a warm hand on his waist to support him as he leaned to the side and kicked his shorts off and onto the floor, leaving him in nothing but his boxers.

 

Tadashi briefly looked down at the dampened bulge in his brother’s underwear before his gaze settled on Hiro’s flustered face.

 

“I haven’t even touched you yet.” He whispered with a bewildered smile.

 

Hiro moaned in reply. He reached down to pull his boxers off but Tadashi’s larger hands engulfed his own, stopping the movement.  

 

Tadashi quickly made up for it by pressing his lips to Hiro’s cheek and then his jaw. 

 

Every time Tadashi slowed his younger brother down or stopped things before they went too far, he always followed up with a kiss or a reassuring brush against the boy’s skin, just so his movements wouldn’t be mistaken for rejection.

 

Tadashi gently pulled the boy’s hands up and placed them on his shoulders.  Hiro responded by lightly digging his nails into his brother’s shirt and anxiously moving his hips back and forth.  He was panting and his body was tense and wouldn’t stop quivering.  

 

Tadashi’s big warm hands ran slowly up his waist and traveled along his ribs.  It was a touch that was meant to relax him but it just made him eager for more.

 

“There’s not hurry…we don’t have to rush.” Tadashi whispered.

 

Hiro took a deep breath and willed himself to calm down. He knew Tadashi liked to take things slow and if Hiro kept squirming wantonly in his lap, then he would only go slower. Tadashi was kind of _frustrating_ like that.

 

Eventually his brother’s soothing touches _did_ calm him down. His breathing slowed and his eyes fluttered shut.  He leaned forward, resting his head against his brother’s chest and inhaled his scent. Tadashi smelled like soap and something fresh but there was always a bit of musk that Hiro _loved_.

 

Hiro shifted his head so that his nose dug into the center of his brother’s chest as he continued smelling him. Tadashi snickered and nuzzled his face into Hiro’s messy black hair.

 

If Hiro let Tadashi have his way, they would probably end up cuddling for hours and never do anything remotely sexual. The only reason this had started is because Hiro had asked for it and Tadashi would do anything he asked as long as they didn’t go too far.

 

Hiro often worried that he was taking advantage of his brother in some way but Tadashi was always reassuring him with loving smiles and constant affection.  Maybe Tadashi spoiled him too much…

 

His body had calmed down but he was still very aroused and his length was pulsing hard and needy against Tadashi’s thigh. Hiro pulled away from his brother’s chest and sat up.  His hands were still resting on his brother’s shoulders and he scratched absentmindedly at the cloth of Tadashi’s shirt before looking up at him.

 

“Okay, I’m good.  More touching please.” He murmured.

 

Tadashi laughed and ran his fingers through Hiro’s hair. His expression softened and his brown eyes swelled with warmth. He gazed at his younger brother with so much love that Hiro could feel the blood rushing to his cheeks.

 

Hiro wasn’t sure what to say so he leaned forward and pressed a kiss to Tadashi’s chin and his brother’s broad shoulders shook with laughter.

 

Then Tadashi’s hands were trailing down towards his waist and Hiro leaned back a bit, using his grip on his brother’s shoulders to keep himself propped up.

 

Tadashi slipped his fingers into the waistband of Hiro’s underwear and slowly started tugging it down. 

 

Hiro kept his head lowered and watched, anxiously digging his nails into Tadashi’s shirt.  His breath hitched as the garment dragged across his bulge and then his length bobbed out.  Because of the way Hiro was sitting, it moved upwards and pressed hard and erect against his navel.

 

Hiro shifted to his knees so that Tadashi could drag the boxers down his thighs then he sat back and lifted his legs to take them completely off.  In this position, he would be giving his brother a _lovely_ view if Tadashi was actually _looking_. Instead, the older brother averted his eyes and kissed Hiro’s foot.

 

Hiro giggled and leaned forward so he was sitting up straight in his brother’s lap.  He hooked his legs behind Tadashi’s waist and shoved his feet under the pillows.

 

Now Hiro was completely naked while Tadashi remained fully clothed.  And yet, _Tadashi_ was the one who seemed reluctant as he grazed his fingertips along Hiro’s spine and stared into the boy’s eyes, studying him.

 

The younger grinned gleefully and then wiggled his hips, causing his length to bob back and forth.  His pattered his fingers against his brother’s shoulders and tugged at him impatiently.

 

Tadashi let out a breathless laugh and then caved. Without looking, he trailed his hand down Hiro’s stomach and curled his fingers around the boy’s length before giving a good, solid _pump_.

 

Hiro gasped and his back arched a bit.

 

He forgot how good it felt to have Tadashi touching him and he eagerly thrust his hips for more contact.

 

Tadashi started out very slow and his grip was light. He was looking everywhere but his lap as he continued stroking the boy.  He watched as Hiro’s face contorted with pleasure.  Hiro stared up at him with half-lidded eyes but they squeezed shut when Tadashi tightened his grip.

 

Tadashi kissed the boy’s face and then his neck and shoulders.  Hiro sighed and continued moaning as he felt his brother’s lips all over him. Tadashi’s kisses weren’t heated and he never used his tongue or left any hickeys.  He preferred to simply press his lips tenderly into the boy’s soft skin and dig his nose into more sensitive spots like the crook of Hiro’s neck. Hiro giggled as Tadashi did _just that_ and his arms circled around his brother’s shoulders, pulling him closer.

 

“Hah.”  Hiro gasped and shuddered when Tadashi pressed his nose into a hot spot under his ear.

 

He tilted his face down and watched his brother’s hand move expertly over his shaft.  He watched as warm fingers collected some of the wetness at the tip and then use it to ease each stroke and suddenly that hand was moving _much_ quicker.

 

“A-ah…ah…ah…ah…” Hiro couldn’t keep himself quiet and his heart was hammering against his chest.

 

Even Tadashi was starting to get worked up. Hiro could feel his brother breathing hotly against his shoulder and his lean body was tensing up at each noise Hiro made. 

 

“Mmhn…” Hiro nuzzled his mouth into his brother’s neck before lightly biting down on it.  He could feel Tadashi’s breath hitch against his ear and the reaction fueled Hiro’s movements, making him bolder.

 

His hands found the waistline of his brother’s shirt and he slipped his fingers underneath it.  He drew it upwards until it was bunched up beneath his brother’s armpits and he was surprised that Tadashi let him.

 

The older brother made no move to take his shirt completely off but he allowed Hiro’s hands to explore his stomach and grope at his chest.  In fact, it caused Tadashi to start stroking him faster and Hiro bit his lip. 

 

Tadashi then leaned back against the headboard and Hiro looked at his face.  He was surprised to see his brother with flushed cheeks and lustful eyes.

 

Usually Tadashi tried very hard not to get aroused and only focused on pleasuring Hiro.

 

Secretly, Hiro longed to drive his brother wild. He wanted to pleasure Tadashi in the same ways Tadashi pleasured him.  He wanted to push him into being more forceful.  He wanted to feel his brother tugging at his hair or shoving him down into the bed.

 

But Tadashi wasn’t like that. His touches were always gentle and tender and just as loving as he was.  His touches were brotherly…or maybe not so brotherly.  Hiro took a split second to ponder on their relationship.

 

Did Tadashi still see him as a brother?

 

Suddenly Tadashi did something _wonderful_ with his wrist and squeezed so tight that Hiro just-

 

“A-AH!”

 

His voice rang out and Tadashi quickly brought their lips together to silence him.

 

Hiro moaned and kissed Tadashi back. It was sloppy because he wasn’t a very good kisser…but he was working on that.

 

He spread his legs and his thighs shook as Tadashi continued working him.

 

_God, he was so close_ …

 

Tadashi’s smell and harsh breathing was making him dizzy with pleasure.

 

He moaned and gasped between panting and shuddering. His entire body was flushed and hot as he began thrusting desperately into his brother’s tight fist. Then Tadashi did that _thing_ with is hand again and Hiro’s eyes rolled back. His body shuddered and he could no longer control his reactions.

 

“Nnn ah! T-Tadash- …HAH!” 

 

Tadashi peppered him in fleeting kisses before dragging his nose up the boy’s neck and whispering lowly into his ear.

 

“Hiro.”

 

_That_ did it. Hiro’s body shuddered violently and he arched.  He buried his face into his brother’s shoulder to muffle the sound as he cried out. His toes curled into the pillows and his hips thrust forward, relishing in blissful release.

 

Tadashi gently stroked him through it and Hiro’s legs twitched with each movement.

 

When his brother went completely limp, Tadashi released him and pulled their bodies flush together.  He wrapped his arms around his little brother and kissed the top of his head as he waited for him to recover.

 

Hiro was finally satisfied and he snuggled closer with dumb smile on his face.  His limbs hung loosely and his body felt like a wet noodle.  There were still a tingling feeling dancing around his tailbone and he sighed contently.

 

“Feel better now?” Tadashi asked.

 

“S’awesome.” Hiro slurred and Tadashi’s laughter vibrated against his ear.

 

Tadashi rubbed his back soothingly and played with his hair until Hiro had enough will power to sit up again.

 

His eyes widened and his face went beet red when he noticed both of their chests were _covered_ in his cum.

 

Tadashi seemed both amazed and amused.

 

“Shiver me timbers!”

 

“Oh, shut up!” Hiro shoved him in the shoulder and Tadashi snickered.

 

He couldn’t help laughing as well but he paused when he felt the bulge in his brother’s pants.

 

“Wow…you’re really hard.” Hiro said quietly.

 

He shifted his weight against his brother’ lap and Tadashi’s breath hitched.

 

“Do you want me to…” Hiro trailed off and reached for his brother’s belt but Tadashi gently pulled his hands away and kissed his knuckles.

 

“No, it’s okay.” Tadashi whispered with a gentle smile.

 

Hiro nodded and tried to hide his disappointment. He _really_ wanted to return the favor but he wasn’t about to force Tadashi into it.

 

Besides, they were brothers and doing this kind of thing was already…

 

He shook his head and tried his best not to think about it.

 

He pulled away from Tadashi and grimaced at the mess all over his chest and legs.  He moved off the bed and teetered a bit.  His legs felt very wobbly. 

 

“Uh…I’m gonna go take a shower.” He murmured.

 

Tadashi grinned as he watched Hiro walk awkwardly towards the stairs.

 

As soon as he was out of the room, Tadashi took a deep breath and closed his eyes. 

 

“Self control… _self control_.” He whispered to himself before standing up and following Hiro to the bathroom.

 

**Author's Note:**

> Let me know what you guys thought! Want me to write more of this? Want me to set myself on fire? (I understand.)


End file.
